1. Field of the Invention
The present invention relates to a character pattern generator, and more particularly to a character pattern generator for generating character patterns having different typefaces by transforming outline font data to change contour shapes.
2. Description of the Related Art
In information equipment and computers, character patterns are usually read out and output from a memory in which font data are stored for each character in advance in order to display and output characters. Oblique characters, characters having shadow, trimmed characters and the like are generated from each font data. For example, a character type (typeface) includes Mincho typeface, Gothic typeface, Lettre de somme, Printed style, Sosho typeface and the like. In order to increase the number of typefaces, it is necessary to prepare a memory in which character patterns corresponding to the typeface are stored as font data. Consequently, it is necessary to use a large capacity memory which is expensive and uneconomical.
In consideration of a data capacity, development and the like, a method for creating a plurality of typefaces from one font data has been desired. As an example of the prior art, a pattern transforming method has been proposed in which outline font data and attribute data belonging to a pattern shape for a control point are prepared, and a transformation parameter for pattern transformation is set to transform the shape of the end of the outline font data so that typefaces having different contour shapes are generated (see Japanese Unexamined Patent Publication No. Hei 3(1991)-234559).
FIGS. 12(a) to 12(c) are diagrams showing an example 1 of the processing of transforming outline font data according to the prior art and a pattern transforming method described in the Japanese Unexamined Patent Publication No. Hei 3(1991)-234559. In the case where the shape of an element (a contour line on the upper side of longitudinal stroke) shown in FIG. 12(a) is transformed into an element whose typeface has a sharp end shown in FIG. 12(c), the contour shape of an outline font is drawn by setting, as control points, the midpoint of the element and points which are lowered from the end-points of on the right and the left of the longitudinal stroke by an arbitrary numeric value as shown in FIG. 12(b). Thus, a typeface having the sharp element is obtained by transformation.
The shape of an end can tentatively be changed as described in the Japanese Unexamined Patent Publication No. Hei 3(1991)234559. However, the shape to be transformed interferes with the design of the generated character. Consequently, it is impossible to perform transformation of high quality.
FIGS. 13(a) to 13(c) are diagrams showing an example 2 of the processing of transforming outline font data according to the prior art. In the case where the shape of an element shown in FIG. 13(a) is sharpened, the same processing as in the description of FIG. 12 is performed. Consequently, the contour shape of an outline font is drawn by setting, as control points, the midpoint of the contour line (element) of longitudinal strokes, and the points which are lowered from the endpoints of on the right and the left of the longitudinal stroke by an arbitrary numeric value so that a typeface having the sharp element is generated as shown in FIGS. 13(b) and 13(c). However, the contour which does not need to be transformed into the generated shape is also transformed. Consequently, the quality of the generated character is extremely lowered.
This is because the control point is set without taking the pattern shape of the outline font data (which is formed by the Bezier curve) into consideration.
Furthermore, since a constant value is input as the amount of movement of the control point, all portions which are to be transformed are transformed in the same way. Consequently, the processing of transformation cannot be performed effectively.